2 milliseconds

Time it takes Google’s new tool to detect a stranger looking at your phone –

Google has claimed to have invented a system that tells you when nosey parkers are looking over your shoulder at your phone. Powered by machine learning, it uses a phone’s front-facing camera to pick out faces that don’t belong to the owner.

Its creators, Google researchers Hee Jung Ryu and Florian Schroff, say it can protect you “from onlookers in a crowded space such as the subway or an elevator”.

In a video they published on Youtube ( www.snipca.com/26380), the camera on a Google Pixel phone detects the stranger’s face, then frames it inside a red box (see screenshot). It also adds rainbow ‘vomit’, which is a popular special effect in online videos.

The researchers, who call the feature an ‘electronic screen protector’, claim it works in many different lighting conditions and with several head poses, making it “quick, robust, and accurate”.

They say it detects a gaze within two milliseconds, and identifies it as a stranger within 47. It appears to work so quickly that even a passing glance would be detected.

The project is experimental at the moment, and there’s no indication that Google will add it to Android. But it’s a prime example of the company’s research into how artificial intelligence (AI) can be used on phones and tablets.

Other AI features in phones include tools that automatically detect numbers and addresses when you’re copying and pasting text, and suggesting pre-written replies to your emails.